Today i was parking my car with the radio off, and hear a slight knocking noise at idle... it wasnt a constant knock, it just seemed to knock at the lower RPMs. Take it around the block and everything seemed fine with just the normal motor chatter. Park it and theres goes the knock.

Heres the thing, the motor was fine before today. With the oil changed every 2500 miles. I have maintained this motor very well.. and today i put all my A/C components in and got it recharged. Air is ICE COLD now.. and today it starts to make a knocking sound. Could it be the A/C compressor? i notice that once i flip the A/C on, i hear no knock.. with the A/C off i hear the knock at idle and seems to go away as i rev the motor. any comments, advice??

 

 

see if you can isolate where the knock is comming from. if its a hollow sort of thud comming from the block that you will be doing a motor swap soon. otherwise it could just need a valve adjustment. lost motion assemblies could be worn too.